Lens structure for a combination signal lamp

ABSTRACT

A lens structure for a combination signal lamp for use in automobiles is comprised of at least two lens pieces joined with each other at their side walls. The side wall of one of the two lens pieces is provided with an exposed, vertical dovetail groove. The side wall of the other of the two lens pieces is provided with a vertical dovetail projection which fits in said dovetail groove. The side wall of the other lens piece also has bulging ridges running on the bilateral peripheral margins, which ridges have their outer surface lying in the same plane as that of the outer surface of the dovetail projection. The side wall of said one of the lens pieces has thick wall portions defining the dovetail groove and has engaging steps running on the bilateral peripheral margins of this side wall. The outer surfaces of these engaging steps lie in the same plane as that of the innermost surface of the dovetail groove. When these two lens pieces are assembled, the dovetail projection fits in the dovetail groove, and the engaging steps engage the bulging ridges, forming a horizontal groove between the lower portions of the side walls. An adhesive is filled in this horizontal groove to establish firm bonding between these side walls. This unique arrangement simplifies the manufacturing process immensely, enhancing the productivity and lowering the cost of manufacture remarkably.

United States Patent 1191 Primary ExaminerSamuel S. Matthews Assistant ExaminerRussell E. Adams, Jr. Attorney, Agent, or FirmWenderoth, Lind & 'Ponack Hasegawa [.451 Apr. 9, 1974 LENS STRUCTURE FOR A COMBINATION [57] ABSTRACT SIGNAL LAMP a A lens structure for a combination slgnal lamp for use Inventor: Aklhlko Hasegawa, Kawasaki, Japan in automobiles is comprised of at least two lens pieces [73] Assigneez Ichiko Industries Limited, Tokyo, joined with each other at their side walls. The side Japan wall of one of the two lens p1eces is provided w1th an exposed, vertical dovetail groove. The side wall of the Flledi Feb- 7, 1973 other of the two lens pieces is provided with a vertical dovetail projection which fits in said dovetail groove.

[21] Appl' (L244 The side wall of the other lens piece also has bulging ridges running on the bilateral peripheral margins,

[ Foreign Application Priority Data which ridges have their outer surface lying in the same Feb. 11, 1972 Japan 47-17094 plane as t at of the ut r urfa of the tail pr v jection. The side wall of said one of the lens pieces has [52] U.S. Cl 240/l06.1, 240/83, 240/415, thick Wall portions defining the dovetail groove and 240/4155 has engaging steps running on the bilateral peripheral [51] Int. Cl. F2lv 5/04 margins of this side wall. The outer surfaces of these [58] Field of Search 240/83, 41.5, 41.55, 106, engaging steps lie in the same plane as that of the in- 240/106.1; 46/25 nermost surface of the dovetail groove. When these two lens pieces are assembled, the dovetail projection [56] References Cited fits in the dovetail groove, and the engaging steps en- UNTTED STATES PATENTS gage the bulging ridges, forming a horizclJntal groove between the lower portions of the side wa ls. An adhesive is filled in this horizontal groove to establish firm 3:410:474 11/1968 Keil 46/25 bonding belwee" these side walls- This unique rangement simplifies the manufacturing process immensely, enhancing the productivity and lowering the cost of manufacture remarkably.

3 Claims, 10 Drawing Figures PATENTEDAPR 9 I974 SHEU 1 BF 3 FIGJ FIG.3

PATENIEUAPR 9 1974 3 803 403 SHEET 3 BF 3 FIG.&

LENS STRUCTURE FOR A COMBINATION SIGNAL LAMP BACKGROUND OF THE INVENTION a. Field of the Invention The present invention is concerned with a combination signal lamp, and more particularly, it relates to a lens structure of the aforesaid lamp prepared in an integral body, such as the combination of a tail lamp and a turn signal lamp used in automobiles.

b. Description of the Prior Art Lens structures for combination signal lamps for automobiles are usually made with molded plastic lens pieces. It is, however, technically impossible to mold a plurality of plastic pieces simultaneously into an integral combination lens structure, because of the fact that these lens pieces are of different colors. Therefore, the conventional lens structures of this kind have been produced by the following complicated steps.

One of the conventional production methods comprises separately moulding the required lens pieces of different colors, while forming rough surfaces for those walls of the lens pieces which are to be connected together, and then bonding them together by the use of an adhesive.

Another conventional production method uses a metal mold provided with at least one space for accommodating a pre-fabricated lens piece of a first color. In use, one places this pre-fabricated first lens piece in place in said space and then molds a fresh lens piece of a second color integrally with said first lens piece in the metal mold, thus welding these at least two pieces together. In each of these prior methods said lens pieces are given a roughening treatment at the connecting surface or are given mutually engaging portions locally on the abutting side surfaces to increase the welding force or joining force of these surfaces.

However, these conventional producing methods have the following drawbacks. In the first-mentioned method, the adhesive used requires 1 2 hours to harden. Therefore, the bonded lens pieces have to be left at rest for this time until a firm bond is established therebetween. Thus, the manufacture of the lamps required complicated steps and the production efficiency was low.

Moreover, the other method described above, on the other hand, requires the use of a mold having a size sufficient for accommodating the pre-fabricated lens piece or pieces, and will have the troublesome steps of mounting these pre-fabricated lens pieces in the space within the metal mold for each manufacturing process, thus lowering the production efficiency. Furthermore, there may arise the inconvenience that, when lighted up, the color of the pre-fabricated lens piece is transmitted to the later-molded lens piece at the junction of these lens pieces that the mounted pre-fabricated lens piece may break at the time of final molding.

SUMMARY OF THE INVENTION Though the present invention belongs to the firstmentioned prior method which uses an adhesive, a primary object of the present invention is to provide a lens structure for a combination signal lamp which does not require the troublesome step of holding the lens pieces together in tightly pressed state for a sufficiently long time until these lens pieces become firmly bonded together as has been practiced conventionally, and which, accordingly, can be mass produced efficiently.

Another object of the present invention is to provide a lens structure for a combination signal lamp of the type described in which the lens pieces are so firmly bonded to each other that they can withstand the forces tending to separate the lens pieces from each other, in spite of the fact that an adhesive is used.

Still another object of the present invention is to provide a lens structure for a combination signal lamp of the type described, which prevents the infiltration of water and moisture into the junction of the bonded lens pieces.

Yet another object of the present invention is to provide a lens structure for a combination lamp of the type described, which, during mass production, is free from the fear of developing faulty products or products of poor quality due to, for example, superposed layer of colors noted at the junction of the lens pieces.

These and other objects as well as the features and advantages of the present invention will become apparent by reading the following detailed description of several embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a side elevation, partly in section, of an embodiment of the combination signal lamp according to the present invention, showing two lens pieces connected together.

FIG. 2 is a segmentary sectional view of the same, taken along the line II II in FIG. 1.

FIG. 3 is a segmentary sectional view of the same, taken along the line III III in FIG. 1.

FIG. 4 is an end view of that wall of one of the two lens pieces which is to be connected to the wall of the other one of the lens pieces.

FIG. 5 is an end view of that wall of the other one of the two lens pieces to be connected to the wall of said one of the lens pieces.

FIG. 6 is a fragmentary sectional view, taken along the line Vl VI in FIG. 4.

FIG. 7 is a fragmentary sectional view, taken along DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, A represents generally a first lens piece and B a second lens piece. The first lens piece A has a side wall 1, and the second lens piece B has a side wall 2. These lens pieces A and B are united together at the surfaces of these side walls 1 and 2.

The side wall 1 of the first lens piece A is provided, on its outer surface, with an exposed vertical dovetail groove 3 extending from the top to the bottom of this wall. Thick portions 4 are provided on the opposite sides of this dovetail groove 3 to form this groove. On

the peripheral marginal portions of said thick portions extending on both sides of the groove in such a way as to flank this groove starting downwardly from the top of each thick portion, there are formed engaging steps having a given width W and lying on the same plane as that of the innermost surface 3' of said dovetail groove 3, as best shown in FIGS. 5 and 7. The bottom end of these thick portions 4 do not extend up to the lowermost edge of said side wall 1, and forms at the bottom portion of said side wall 1 a thin wall portion 6 of a given width W The outer surface of this thin wall portion lies on the same plane as that of the innermost surface 3 of said dovetail groove 3.

The side wall 2 of the second lens piece B is provided, on its outer surface, with a vertical dovetail projection 7 which has a configuration and dimension complementary to those of the groove 3 so as to fit in said dovetail groove 3. This projection 7 is provided at the site of the side wall 2 corresponding to the position of said dovetail groove 3. As shown in FIGS. 4 and 6, the upper portion of the dovetail projection 7, joins at the opposite sides thereof into bulging ridges 8 running therefrom downwardly on the bilateral peripheral margins of the side wall 2. These bulging ridges 8 have a width W corresponding to that of said engaging steps 5, 5 and are complementary in configuration to said engaging steps. The bottom edge of the dovetail projection 7 does not extend up to the bottom edge of said side wall 2, leaving therebetween a width W substantially, the same as that of the thin wall portion 6.

The manner in which the first and the second lens pieces A and B are fitted together will now be described. These first and second lens pieces A and B having the aforesaid configurations are first brought to the positions shown in FIGS. 6 and 7 in which the lens piece A is positioned closely abovethe lens piece B so that the side wall 1 is located directly above the side wall 2. Then, the vertical dovetail projection 7 of the second lens piece B is slid into the vertical dovetail groove 3 having a complementary shape so that said dovetail groove 3 and said'dovetail projection 7 are brought into engagement with each other. These first and second lens pieces A and B are thus united together firmly because of the fit-engagement established between the dovetail groove and the dovetail projection, and also between said bulging ridges 8 of the second lens piece B and said engaging steps 5 of the first lens piece A, so that normally these two lens pieces can not get out of place. However, in this condition, the lens pieces can be slided relative to each other in directions opposite to those indicated by the arrows in FIGS. 6 and 7 to'be separated from each other. According to the present invention, however, there is formed a thin wall portion 6 at the lower end portion of the side wall of the first lens piece A, and the dovetail projection 7 is formed so as not to extend completely to the bottom edge of the side wall 2 of the second lens piece B. Thus, there is formed a horizontal groove 9 between the lower portions of the side walls 1 and 2 when said two lens pieces are assembled together. In this horizontal groove 9 is placed an adhesive to fix these lens pieces in place. For this purpose any kind of adhesive intended for plastic materials can be used, but it is desirable to use a hot-melt synthetic adhesive having a melting point of about I50 C.

It should be noted that an opaque light-shielding paint may be applied to the outer surface of either one of the two side walls 1 and 2 before uniting the first and second lens pieces A and B together to keep the colored light rays of one lamp from being transmitted into the lens piece material of the adjacently disposed other lamp when said one lamp is lighted.

An advantage of the present invention is that the engagement 7 resists any external pulling forces applied to these 7 well copes with any external pull-out forces applied to these lens pieces A and B in a direction substantially perpendicularly to the planes of the abutting faces of the side walls 1 and 2. In addition, the engagement between the engaging steps 5 and the bulging ridges 8 exerts a sufficient resistance against any external forces to cause mutual sliding of these two lens pieces A and B leading to displacement of these lens pieces. Thus, according to the present invention, the mechanical uniting force between the first and second lens pieces A and B is obtained mainly by said engagements between the dovetail groove and thedovetail projection and also between the engaging steps and the bulging ridges. The adhesive is used only to hold and maintain the state of the aforesaid engagements. Therefore, the combination signal lamp produced in accordance with the present invention has a very high uniting force as compared with those combination signal lamps of the prior art which are arranged so that their mechanical strength also is borne by the adherency of the adhesive and the connected lens pieces will never separate from each other casually because of the very firm uniting force mechanically established between the lens pieces.

Another advantage of the present invention lies in that there is no necessity of keeping the first and second lens pieces in pressed state for a long time until the adhesive filled in the groove 9 becomes set, because the lens pieces are united together primarily by said engagements. It is sufficient to leave the united lens pieces together at rest for a very short predetermined time after the application of the adhesive. Moreover, there is no particular need of keeping the adhesiveapplied lens pieces at rest. Thus, it is possible to mass produce the combination signal lamps efficiently by a very simplified process.

Still another advantage of the present invention lies in the fact that, the adhesive fills the space between the abutting wall surfaces of the respective lens pieces, whereby the combination signal lamp prevents the infiltration of moisture or gas into this junction.

A further advantage of the present invention is found in the fact that, unlike the conventional integral molding process which uses a large-size metal mold for housing a pre-molded lens piece or pieces and which molds the final lens piece together with the pre-molded lens pieces in said mold to produce an integrally fused lamp assembly, there can be obtained a very much improved productivity, and what is more, the products of the present invention are substantially faultless. This is because the products of the present invention are made by a simple and sure operation of merely putting together the respective lens pieces molded separately beforehand and of applying the adhesive subsequently between said space.

FIGS. 9 and 10 show a modified example of the present invention. In this example, the side wall 1 of the lens piece A is similar in construction to the side wall 1 of the preceding example in that it has the dovetail groove 3 and the engaging steps 5, with the exception that the thick wall portions 4 located on both sides of the dovetail groove are joined to each other at their lowermost end edges by an elongated connecting projecting member 11 having its outer surface lying in the same plane as the planes of the outer surfaces of said thick wall portions and that a groove is formed under this connecting member 11 to be filled with the adhesive 10. The other features and arrangements of this example are substantially the same as those of the preceding example. It will be understood easily, therefore, that the combination signal lamp of this example also exerts the advantageous features similar to those of the preceding example.

The foregoing descriptions in conjunction with the accompanying drawings have been made with resepct to embodiments in which only two lens pieces are connected together. It should be understood, however, that the present invention is not limited to these embodiments. It will be needless to say that the present invention can be modified as desired and can be applied also, in addition to the aforesaid embodiments, to a combination lamp assembly comprised of three lamps, for example, a tail-lamp, a turn signal lamp, and a stop lamp, without departing the spirit and the scope of this invention. Description has been made also to instances where the side walls of these two lens pieces have one vertical dovetail groove and one complementary vertical dovetail projection for each side wall. It will be clearly understood, however, that more grooves and projections may be formed and that, in addition to said dovetail grooves and projections, there may 'be provided further recesses and protrusions arranged to engage each other.

I claim;

l. A lens structure for a combination signal lamp, comprising: 7

at least two lens pieces each having a side wall to be connected together, each side wall having horizontal upper and lower edges and having bilateral pe- 6 ripheral margins extending vertically between said edges the side wall of one of said two lens pieces having at least one exposed, vertical dovetail groove,

the side wall of the other one of said two lens pieces having at least one vertical dovetail projection with a configuration complementary to that of said dovetail groove to fit therein,- said projection being formed at a site corresponding in position to that of said groove,

the side wall of said other one of the lens pieces further having, ridges extending from its bilateral peripheral margins, the outer surfaces of which lie in the same plane asthat of the outer surface of said dovetail projection,

the side wall of said one of the lens pieces further having grooves on its bilateral peripheral margins, the inner surfaces of these peripheral grooves lying in the same plane as that of the innermost surface of the dovetail groove,

said peripheral grooves having configurations complementary to those of said ridges so as to engage the latter;

each of said side walls having a horizontal groove on their lower edges such that when said side walls are connected together, said horizontal grooves form a channel to be filled with adhesive.

2. A lens structure for a combination signal lamp according to claim 1, in which said dovetail groove is closed at its lower end by an elongated connecting projecting member, the outer surface thereof lying in the same plane as the outer edge of said dovetail groove.

with a light-shielding opaque material.. 

1. A lens structure for a combination signal lamp, comprising: at least two lens pieces each having a side wall to be connected together, each side wall having horizontal upper and lower edges and having bilateral peripheral margins extending vertically between said edges the side wall of one of said two lens pieces having at least one exposed, vertical dovetail groove, the side wall of the other one of said two lens pieces having at least one vertical dovetail projection with a configuration complementary to that of said dovetail groove to fit therein, said projection being formed at a site corresponding in position to that of said groove, the side wall of said other one of the lens pieces further having, ridges extending from its bilateral peripheral margins, the outer surfaces of which lie in the same plane as that of the outer surface of said dovetail projection, the side wall of said one of the lens pieces further having grooves on its bilateral peripheral margins, the inner surfaces of these peripheral grooves lying in the same plane as that of the innermost surface of the dovetail groove, said peripheral grooves having configurations complementary to those of said ridges so as to engage the latter; each of said side walls having a horizontal groove on their lower edges such that when said side walls are connected together, said horizontal grooves form a channel to be filled with adhesive.
 2. A lens structure for a combination signal lamp according to claim 1, in which said dovetail groove is closed at its lower end by an elongated connecting projecting member, the outer surface thereof lying in the same plane as the outer edge of said dovetail groove.
 3. A lens structure for a combination signal lamp according to claim 1, in which the exposed surface of the side wall of at least one of said two lens pieces is coated with a light-shielding opaque material. 